Hi I have a 2000 GMC 4×4 pickup and I sprayed your internal frame coating inside the horizontal pipes that connect the left and right side frame rails as they were rusting . They are exposed to the weather somewhat and I would like to know if I should top coat the internal frame coating with anything or just leave it that green color . I live in the northeast and it will get snow and salt on it . Any help much appreciated . Thank’s David.